metastasen

Metastases are secondary malignant growths that arise when cancer cells disseminate from a primary tumor to distant organs. In German, the term is Metastasen. Metastases occur when cancer cells detach from the primary tumor, invade surrounding tissue, and enter blood vessels or lymphatic channels. They travel through the circulatory system or lymphatic system, survive in circulation, and extravasate at distant sites, where they colonize and form new tumors. Metastasis is a hallmark of malignant disease and is the main cause of cancer-related mortality.

Common routes include hematogenous spread via blood, lymphatic spread, or transcoelomic spread across body cavities. Common sites are the liver, lungs, bones, and brain. The pattern of metastasis often mirrors the origin of the primary tumor; for example, breast cancer frequently spreads to bone or liver, colorectal cancer to the liver, and lung cancer to the brain. Melanoma can spread widely.

Diagnosis and staging rely on imaging and tissue confirmation. Metastases are suspected when distant lesions are observed on imaging; confirmation is obtained by biopsy showing histology consistent with the primary cancer. Staging uses the TNM system, with M1 indicating the presence of distant metastasis.

Treatment and prognosis depend on the cancer type and metastatic burden. Systemic therapies (chemotherapy, targeted therapy, hormone therapy, immunotherapy) are commonly used, often alongside local therapies (surgery or radiotherapy) to relieve symptoms or control disease. Prolonged survival is possible for some cancers, but prognosis varies widely and metastasis generally indicates advanced disease. Management aims to extend survival and maintain quality of life.